Method of manufacturing explosives.



U-NITED STATES HARVEY W. IVILEY, OF WASHINGTON, DIS'IttlC'l OF COLUMBIA, ASSIGXOR PATENT OFFICE.

-'TO THE MARSDEN COMPANY, OF PHILADELPHIA, PEXXSYLVAX A.

METHOD OF MANUFACTURING EXPLOSI VES.

SPEGIFICATION forming part of Letters Patent N 0. 673,347, dated April 30, 1901.

l Application filed February 24, 1899. Serial No. 706.725. 1N0 specimens.)

To all whom, it may concern.-

Be it known that I, HARVEY W. WILEY, a citizen of the United States, residingat Washington, in the District of Columbia, have in- 5 vented certain new and useful Improvements in Methods of Manufacturing Explosives, of which the following is a specification.

In the preparation of the material I take vegetable pithfor instance, the pith of In- IO dian corn-and comminnte the same, preferably heating the pith, so as to secure the cell'u lar part of the pith as far as possible free from moisture.

\Vhile dry pith will absorb about eight ti mes :5 its weight of nitroglycerin, I have found-that as thus charged the liquid escapes too readily and that it is preferable to limit the absorplion to from thirty-three per cent. to one hundred per cent. of the weight of the pith. This,

ho\vever,.'it is difiicult to do and secure a uniform result, someparticles of the pith becom- 'ing fully saturated, while others take up but little of the liquid, the product being practically unfit for use.

After various experiments I have found that a uniform product cannot well be obtained without fuilysat-u rating every particle of pith and that then by pressure the excess can be removed, leaving'any desired amount in the pith, thereby seburinga dynamite consisting of particles of eoinminnted pith partiallybutuniformly charged with nitroglycerm.

Owing to the great viscidity and veecific gravity ofnitroglyceri Lflabout 1.6,) it is sometimes diflicult to regularly saturate the particles of pith, and to overcome this objection I dilute the nitroglycerin or dissolve it in any suitable liquid of less specific gravity capa- 40 bleof being evaporated at a comparatively low temperature, thus securing a more tiuid and dilute solution capable of ready absorption by the pith, and I then remove the volatile solvent by heat, recovering it for reuse in any suitable manner, and thus secure also the result of leaving in the cells of the pith only a limited quantity of nitroglycerin, while uniformly distributing the same in all parts of every pith particle. Among other-solvents which maybe employed are methyl-alcohol or wood-spirit, or, preferably, low-grade petroleu n1 ether, which volatilizes at about from 45 to centigrade and which is inexpensive and easily recovered and reused.

As illustrative of my mode of operation I would state that one hundred grams of nitroglycerin are dissolved in eight hundred grams of petroleum ether, and with this I saturate one hundred grams of pith. The mixture is then heated to from to to centigrade until the volatile liquid is removed, when the pith will be found to be properly charged.

For many pnrposes,and especially for transportation, the material as it exists after the removal of the volatile liquid will be of undesirable bulk and its parts too far separated to secure maximum explosive results. I therefore compress the same, which may be done without expelling the liquid, until the mass is so consolidated that it will explode properly, while its bulk is thus so reduced that it may be commercially transported. 'I have found that the pith is a most satisfactory absorbent and that unlike many others it is free from any matter likely to affect the liquid; It is exceedingly combustible, so that it is consumed upon the explosion, leaving practically no ash or deposit, while it holds the particles of liquid so regularly and uniformly separated that it is a most satisfactory retainer, and the dynamite thus made has better keeping qualities and yields a higher detonating force than can be secured by the use of ether absorbents.

Iam aware that pithy substances have heretofore been used for absorbing nitroglycerin; but in these cases the substances have been previously treated with an acid or alkali for the purpose of removing iiquo-celluloses and 'pentosans and then compressed before the nitroglycerin is absorbed. By this method it is impossible to get a uniform distribution of the nitroglycerin to all parts of the mass, and especially an excess of nitroglycerin will exist at the surface of the compressed blocks, and thus the same is in the most dangerous condition to produce decompositions and explosions. In my process the nitroglycerin is previously dissolved in an appropriate solvent, in which condition it can be uniformly absorbed by the untreated natural pithy substance, and thus deposited in molecular contact with all parts of the absorbent material, thus securing a. perfectly even distribution and avoiding any excess at the surface.

I claim-as my invention- In the manufacture of dynamite, comminuting vegetable pith, saturating the same with a solution of nitroglycerin in a volatile liquid and then-removing the latter by evap-. 

